Age-related characteristics of the distribution and attachment of chordae tendineae to the valves of the human heart

In 50 cardiac preparations of persons of various age (children, teenagers, adolescents, persons of mature and elderly age) distribution of various branches of the tendinous chordae (basic, marginal, commissural, rough zone) and level of their fixation to the ventricular surface of the right and left cusps of the atrioventricular valves have been studied. The tendinous chordae in direction from the apex of the papillary muscles towards the cusps of the atrioventricular valves are divided into the branches of the 2d--9th orders. Total quantity increase of the tendinous chordae is noted in the mature age, especially those of the 1st order in the left ventricle, and their decrease in the elderly age with an increase of the chordae of the 4th, 5th and 6th orders. Single chordae of the 8th and 9th orders can be found in elderly persons. Certain age specificities are revealed in fixation of various tendinous chordae to the cusps of the atrioventricular valves; they are surely connected with functional peculiarities of their different zones, that ensure air-tightness of the atrioventricular openings. There are quantitative differences of the tendinous chordae, fixed to certain cusps of the left (anterior) and right (anterior, posterior) atrioventricular valves; this is evidently connected with the role of the cusps mentioned in the mechanism of the valves closing.     

Demonstration of a beta-casomorphin immunoreactive material in the plasma of newborn calves after milk intake

Blood was collected from newborn calves before and after their first milk intake after birth; extracts of plasma were assayed by radioimmunoassay for the presence of beta-casomorphin-7 immunoreactive materials. No beta-casomorphin immunoreactivity was found in samples collected before milk ingestion; however, in samples collected after milk ingestion a beta-casomorphin-7 immunoreactive material was detected. Chromatographic characterization showed that this material was not identical with beta-casomorphin-7 but might rather represent a precursor thereof. The material proved resistant to enzymatic attack during a 30-min incubation period at 37 degrees C in the plasma of newborn calves, whereas beta-casomorphin-7 was degraded under these conditions. A physiological significance of beta-casomorphin-7 eventually cleaved from such a precursor material at any site in the newborn mammal is suggested.     

Investigation of pallidofugal influences on hypothalamic activity

In chronic experiments on nine cats electrical stimulation of the posterior zones of the lateral hypothalamus led to reproduction of a conditioned food-getting reflex produced previously in response to clicks. During stimulation of the globus pallidus a food-getting reflex also appeared in 3 of 10 zones studied, but it did so only irregularly. In response to combined stimulation of the hypothalamus and these three zones of the globus pallidus facilitation of this reflex was observed: its intensity was increased and its latent period shortened. Stimulation of other areas of the globus pallidus inhibited the food getting reflex of hypothalamic origin on account of the intensification of purposeless motor responses. Stimulation of the globus pallidus evoked desynchronization of spontaneous hypothalamic electrical activity. After bilateral electrolytic destruction of the globus pallidus and its principal efferent pathway (the ansa lenticularis) no conditioned food-getting reflex was reproduced during hypothalamic stimulation. After pallidectomy the amplitude of the spontaneous waves and evoked potentials was reduced by a statistically significant degree in the hypothalamic zones tested. The results are evidence of the existence of regulatory functional influences of the globus pallidus on the lateral hypothalamus.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 6, No. 6, pp. 592–601, November–December, 1974.     

Ion balance in tomato cultivars differing in salt tolerance. I. Sodium and potassium accumulation and fluxes under moderate salinity

The magnitude of sodium and potassium fluxes in Lycopersicon escutentum cuhivars Ace and Edkawi (Edkawi is considered more sait-tolerant I was evaluated in planls grown for 10 days in aerated Hoagland solution with the addition of 25 or 100 mM NaCl. Ion accumulatiun in different plant pans, ion concentration in xylem exudate. transpiration and membrane leakiness were measured. Both cultivars responded very similarly to these levels of salinity in terms of growth. No conspicuous differences in membrane leakiness were observed. Net uprake rates were calculated from ion contents data. Potassium uptake rates were lower in salinized planls than in controls, especially in cv. Aee. Potassium/sodium selectivity ratios were much higher in Edkawi than in Ace. and higher in shoot uptake rates than in xy lem exudate. This indicates that Edakw i has a higher capacity to retain potassium under salinity, a character which could contribute to its salt-tolerance.     

Human appropriation of net primary production as driver of change in landscape-scale vertebrate richness

Aim

Land use is the most pervasive driver of biodiversity loss. Predicting its impact on species richness (SR) is often based on indicators of habitat loss. However, the degradation of habitats, especially through land-use intensification, also affects species. Here, we evaluate whether an integrative metric of land-use intensity, the human appropriation of net primary production, is correlated with the decline of SR in used landscapes across the globe.

Location

Global.

Time period

Present.

Major taxa studied

Birds, mammals and amphibians.

Methods

Based on species range maps (spatial resolution: 20 km × 20 km) and an area-of-habitat approach, we calibrated a “species–energy model” by correlating the SR of three groups of vertebrates with net primary production and biogeographical covariables in “wilderness” areas (i.e., those where available energy is assumed to be still at pristine levels). We used this model to project the difference between pristine SR and the SR corresponding to the energy remaining in used landscapes (i.e., SR loss expected owing to human energy extraction outside wilderness areas). We validated the projected species loss by comparison with the realized and impending loss reconstructed from habitat conversion and documented by national Red Lists.

Results

Species–energy models largely explained landscape-scale variation of mapped SR in wilderness areas (adjusted R²-values: 0.79–0.93). Model-based projections of SR loss were lower, on average, than reconstructed and documented ones, but the spatial patterns were correlated significantly, with stronger correlation in mammals (Pearson's r = 0.68) than in amphibians (r = 0.60) and birds (r = 0.57).

Main conclusions

Our results suggest that the human appropriation of net primary production is a useful indicator of heterotrophic species loss in used landscapes, hence we recommend its inclusion in models based on species–area relationships to improve predictions of land-use-driven biodiversity loss.     

Induced responses in three tropical dry forest plant species – direct and indirect effects on herbivory

Induced changes in plant quality are hypothesized to reduce herbivore numbers and subsequent damage to the plant. The resultant decrease in herbivory may be due to direct negative impacts on herbivores, through the reduction in foliage quality as food, or due to indirect effects of plant-induced traits interacting with the third trophic level, increasing predation and parasitism rates on herbivores. The relative importance of induced responses as direct and/or indirect defenses has not been evaluated in natural systems. Moreover, few studies have evaluated the influence of early-season damage on late-season herbivory in natural systems, particularly in the tropics. The presence of induced responses and subsequent impact on folivory as a consequence of early-season damage were evaluated in three plant species ( Croton pseudoniveus , Bursera instabilis and Piper stipulaceum ) in a tropical dry forest in Mexico. A two-factorial experiment was applied to determine if induced responses influenced subsequent herbivory directly, by reducing foliage quality, or indirectly, through their interaction with parasitoids and predatory arthropods. Plants from all three species with reduced early-season damage had higher herbivory rates through the rest of the growing season, compared to plants that were damaged during leaf expansion. Chemical analyses showed that early-season damage induced the production of total phenolics and condensed tannins for C. pseudoniveus and B. instabilis , respectively. The mechanism by which these compounds affected subsequent herbivory was most likely by directly reducing foliage quality as food for herbivores, given that predatory arthropods and parasitoids had no effects on herbivory in this study. I conclude that early-season damage in these three species influenced later-season herbivory through the induction of plant responses that may act to reduce plant quality as food for herbivores.     

Coordination of movements of the tube feet and arms of ophiurans during locomotion

The role of the tube feet in locomotion of the ophiuranAmphipholis kochii Lütken is examined. During stepping movements the anterior tube feet attach themselves to the supporting surface and at the end of the step they detach themselves from it. The signal for detachment is deviation of the foot into the posterior (relative to the direction of motion) position. Because of this arrangement of the "stepping" mechanism of the tube feet the task of coordinating their activity with arm movements is greatly simplified. The feet "automatically" attach themselves to the support when the arm which carries them plays the role of motor; conversely, they detach themselves from the support when this arm moves forward. The CNS thus evidently does not participate in foot and arm movement coordination. It simply assigns the general direction of motion to all the feet and coordination takes place "automatically" as a result of the special properties of the "stepping" mechanism of individual feet.Institute of Oceanology, Academy of Sciences of the USSR, Moscow. Institute of Problems of Information Transmission, Academy of Sciences of the USSR, Moscow. Moscow State University. Translated from Neirofiziologiya, Vol. 8, No. 6, pp. 633–639, November–December, 1976.     

Coordination of arm movement during locomotion in ophiurans

During movement of the ophiuranAmphipholis kochii Lutken, any one of its arms can point forward and, consequently, any arm can perform different functions. The arm, when separated from the ophiuran together with the adjacent part of the nerve ring, is capable of complex motor acts, including locomotion. Division of the nerve ring in the ophiuran disturbs coordination of the arms. The results of experiments in which one or more arms were amputated showed that the choice of leading arm and of method of locomotion depends mainly on afferent impulses received from the arms. The results indicate that the neural centers of individual arms possess relative autonomy. Coordinated working of the centers is achieved through their interaction. This interaction ensures the distribution of functions between the arms in accordance with the motor task to be undertaken and coordinates the activity of the arms in time. The dominant role in the distribution of functions between the arms is played by the center of the leading arm, which controls the activity of at least the adjacent centers.Institute of Oceanology, Academy of Sciences of the USSR, Moscow. Institute of Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. Moscow State University. Translated from Neriofiziologiya, Vol. 8, No. 5, pp. 529–537, September–October, 1976.     

Aluminium Stress Affects Nitrogen Fixation and Assimilation in Soybean (Glycine max L.)

Nitrogen fixation and assimilation in nodules and roots were studied in soybean (Glycine max L.) exposed to different levels of aluminium (Al) stress (0, 50, 200 and 500 μM). Al at 500 μM induced oxidative stress, which became evident from an increase in lipid peroxidation accompanied by a concomitant decline in antioxidant enzyme activities and leghaemoglobin breakdown. Consequently, there was also a reduction in nitrogenase activity. However, the leghaemoglobin levels and nitrogenase activity were unexpectedly found to be higher in nodules when the plants were treated with 200 μM Al. Of the enzymes involved in nitrogen assimilation, the activity of glutamate dehydrogenase-NADH was reduced in nodules under Al stress, but it was significantly higher in roots at 500 μM Al as compared to that in the control. In nodules, the glutamine synthetase/glutamate synthase-NADH pathway, assayed in terms of activity and expression of both the enzymes, was inhibited at >50 μM Al; but in roots this inhibitory effect was apparent only at 500 μM Al. No significant changes in ammonium and protein contents were recorded in the nodules or roots when the plants were treated with 50 μM Al. However, Al at ≥200 μM significantly increased the ammonium levels and decreased the protein content in the nodules. But these contrasting effects on ammonium and protein contents due to Al stress were observed in the roots only at 500 μM Al. The results suggest that the effect of Al stress on nitrogen assimilation is more conspicuous in nodules than that in the roots of soybean plants.